{
  "abstract": "Grover search provides the generic quantum baseline for symmetric-key recovery by amplifying a reversible public-verification oracle. We investigate whether public round structure can instead shape a variational key register before exact verification. For simplified AES (S-AES), we construct phase separators from S-box differential-distribution constraints, candidate-key-dependent inverse diagnostics, and a global residual Hamming-shell term. Each component has a reversible compute-phase-uncompute realization. We prove a one-sided completeness statement for these diagnostics and derive a conditional lower-tail bound for false keys under a weakly correlated diagnostic model. On ten random three-pair 16-bit S-AES instances, an 18-layer schedule optimized with Adam achieves a mean public-consistent-key probability of 46.78 percent, ranks the correct key first in every run, and limits the largest observed false-key probability to 1.11 percent. The 16-bit study evaluates the induced key-register dynamics without shot sampling, while a separate gate-level S-DES experiment validates the reversible oracle pattern without a key-space phase table. The results establish a controlled reduced-cipher benchmark; they do not claim an attack on full AES or an asymptotic advantage over Grover. Within these limits, the construction provides a useful framework for analyzing how AES structure can be incorporated into quantum algorithms.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.26800",
  "author_total": 1,
  "authors": [
    {
      "name": "Xi Li"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/09xa3bje7ek9m.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.26800",
  "fulltext_url": null,
  "id": "09xa3bje7ek9m",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.26800",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "quant-ph"
    ],
    [
      "openalex",
      "1702|Cryptographic Implementations and Security"
    ]
  ],
  "openalex": "W7214175986",
  "pdf_url": "https://arxiv.org/pdf/2609.26800",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/09xa3bje7ek9m.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:56Z",
      "native_id": "2609.26800",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.26800"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Structured Variational Key Concentration for a Reduced AES Cipher",
  "title_text": "Structured Variational Key Concentration for a Reduced AES Cipher",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:56Z",
  "url": "https://research.draconitic.com/paper/09xa3bje7ek9m",
  "venue": "arXiv",
  "versions": []
}